Two years ago I had a beautiful plant grow in my flower box. I did not plant it. It remained outside year-round. It turns green in spring with white mucus on the stem. In the fall it develops seeds and turns purple. It grew again this year but is now so big I would like to trim it but do not want to kill it. Can you identify it from these pictures and advise how to care for it? I will send the pictures separately.
The Gardener’s Answer
Hi, Vickey in North Carolina: The plant in the pictures you sent looks like Eupatorium capillifolium, commonly referred to as dog fennel. It’s a relative of Joe Pye weed and is native over a large portion of the South and Eastern US. It is hardy in USDA hardiness zones 3-10. A lot of gardeners consider this plant to be a noxious weed and others a fine ornamental. It is commonly found along roadsides and ditches. It is a perennial so it will come back unless you remove the roots. The foliage of this plant has a distinct smell when crushed. It can be cut back after the foliage dies back in the late fall/early winter.